Fabrication of a gecko seta-like structure using polydimethylsiloxane

Abstract

This study proposes the combination of electrochemical tip sharpening, mirror wax plate production, computer numerical control (CNC) imprinting technology, and the polydimethylsiloxane (PDMS) vacuum casting method to produce an innovative process akin to the setae arrangement in gecko feet to create a large-area gecko seta-like structure or gecko tape. This study produced micrometer tip radius probes using electrochemical methods and used CNC to apply imprinting technology to imprint a micrometer pore structure on the mirror wax plate (substrate) via micro-scale probes to be covered with a micro-porous structure of the wax mold, conducting the vacuum casting method by PDMS to create a gecko tape shaped like gecko feet.The results show that the surface roughness of the mirror wax plate produced in this study reaches the nanoscale. After electrochemical tip sharpening, the tip radius of the 0.5mm tungsten rod can be reduced to less than 10μm. The finished gecko tape indicates that using a wax mold to conduct PDMS vacuum casting creates good formability. This indicates the innovative gecko seta-like tape process proposed in this study is greatly feasible. It was also found that the adhesion force increased with the increase of the number of pillars and the increased pillars height of the gecko tape. The average adhesion force of a single pillar, however, decreases with an increase in the number of pillars.